Mr Seldon was a partner at a law firm. When he was required to retire at 65, in line with the firm's policy, he brought a claim for age discrimination.

The employment tribunal found against him. The firm's policy was justified, the tribunal said. It was a proportionate means of pursuing legitimate aims. In this case, the legitimate aims were to do with giving younger staff a chance to progress, helping with workforce planning and limiting the need to expel underperforming partners and so engendering a supportive culture.

This went all the way to the Supreme Court via the Employment Appeal Tribunal and Court of Appeal. Mr Seldon argued that the employer's aims didn't justify direct age discrimination, and that the treatment had to be justified specifically in relation to his case and not the retirement policy generally.

His arguments failed. The Supreme Court said that the firm's aims were social policy aims (inter-generational fairness and preserving the dignity of older workers) rather than individual business needs (cost-cutting or improving competitiveness). And they were legitimate, justifying direct age discrimination.

The case has been sent back to tribunal to decide whether choosing the age of 65 for retirement was a proportionate means of achieving the firm's legitimate aims (rather than, say, 67 or 70). We'll have to wait and see.

Until then, while it might be possible to justify a retirement age, we don't have any guidance on what that age might be. This case certainly doesn't open the door for employers to start retiring staff at 65 without some very careful thought, and a bit more direction from the courts.

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